HT45F4MA datasheet(126/145 Pages) HOLTEK

126 / 145 page

Rev. 1.20

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Rev. 1.20

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HT45F4MA/HT45FH4MA/HT45FH4MA-1

Power Bank Flash MCU

HT45F4MA/HT45FH4MA/HT45FH4MA-1

Power Bank Flash MCU

LVD Operation

TheLowVoltageDetectorfunctionoperatesbycomparingthepowersupplyvoltage,VDD,witha

pre-specifiedvoltagelevelstoredintheLVDCregister.Thishasarangeofbetween2.7Vand4.0V.

Whenthepowersupplyvoltage,VDD,fallsbelowthispre-determinedvalue,theLVDObitwillbe

sethighindicatingalowpowersupplyvoltagecondition.TheLowVoltageDetectorfunctionis

suppliedbyareferencevoltagewhichwillbeautomaticallyenabled.Whenthedeviceispowered

downthelowvoltagedetectorwillremainactiveiftheLVDENbitishigh.AfterenablingtheLow

VoltageDetector,atimedelaytLVDSshouldbeallowedforthecircuitrytostabilisebeforereadingthe

LVDObit.NotealsothatastheVDDvoltagemayriseandfallratherslowly,atthevoltagenearsthat

ofVLVD,theremaybemultiplebitLVDOtransitions.

VD D

V LV D

LV DE N

LV DO

t LV DS

LVD Operation

TheLowVoltageDetectoralsohasitsowninterruptwhichiscontainedwithinoneoftheMulti-

functioninterrupts,providinganalternativemeansoflowvoltagedetection,inadditiontopollingthe

LVDObit.TheinterruptwillonlybegeneratedafteradelayoftLVDaftertheLVDObithasbeenset

highbyalowvoltagecondition.WhenthedeviceispowereddowntheLowVoltageDetectorwill

remainactiveiftheLVDENbitishigh.Inthiscase,theLVFinterruptrequestflagwillbeset,causing

aninterrupttobegeneratedifVDDfallsbelowthepresetLVDvoltage.Thiswillcausethedeviceto

wake-upfromtheSLEEPorIDLEMode,howeveriftheLowVoltageDetectorwakeupfunctionisnot

requiredthentheLVFflagshouldbefirstsethighbeforethedeviceenterstheSLEEPorIDLEMode.

HT45F4MA Datasheet(PDF) 126 Page - Holtek Semiconductor Inc